Esters of hydracrylic acid and imino ethers



. Bio o m'emdf Patented May 22, 1951 STATES PATENT OFFICE Esmasoenmalmymc Aerb'm'tii IMINO ETHERS' Martin L. Fein, Riverside; N. J., and Charles Fisher,- Abington, Pa., assignors to United states gfiAmerica as represented by the Secretar-y of Agricultureniawmga fipiilicationaApril 16, 1948: e SerialNo; 21,544-

reams; (01. 260 -453) created the -act of March a, 1883, as

amendedlApril .30, 1928; 370 O. G. 757) made under the a'et or States of America-- for governmental purposes throughout the world without the payment to us of any royalty thereon;

This invention relates to esters of hydracrylic acid-and has-for an-object the provision ofsuch esters and processes for their preparation.

We have found that f esters of hydracrylic acid are obtained on reacting an alcohol with ethylene 7 cyanohydrin and; hydrogen chloride,- and hydrolyzing the resulting iminoether hydrochloride. 1

This macaron -1's lll ust f -atd by the-following aqua tiohs w erein represents a-hydrocarbon radical freeof substituents other-*trian -naio'gem- I v NH;HGl eatlemania-carnel neceaeac enact The process ofour invention is applicable to V the production of esters of hydracrylic acid in general. Alcohols which can-- be reacted with ethylene cyanohydrin and hydrogen chloride under the conditions of the reaction to yield the cor-respondingsaester of hydracrylic a'cid. include, for example, methyl, :ethyl,, propyl ,.-butyl} o'ctyl' and higher saturated aliphatic alcohols containing a normal or branched carbon atom chain;

allyl alcohol, beta-chloriiallyl and"other chloroallyl alcohols, and-other unsaturated aliphatic alcohols, such: as oleylalc ol; ol;.;- Aroma-tic, alicyclic and heterocyclic alcohols-such asbenzyl alcohol, cyclohexanol and tetrahydrofurfuryl. a1- cohol may also'be usedi :The following examplesiare 'illustra-tive of the inventiom 1. .I,

E ciafihz'ile 'I' Dry hydrogen chloride" was bubbled at about Oto 10 C. into 'a solution of '142 g.-beta-hydroxy= mbutylalcoholin 200' ml. of diethyl ether, until the soluuzion became saturated, which-requiredapproximately fivehoursr Orr standing for about talline precipitate (beta hydroxypropionimin'o"-' butyl ether-hydrochloride)was formed. Most of the free hydrogen chloride was then removed from the reaction mixture by alternately applying vacuum a'fid blowing a stream of dry air through the slurry. Approximately 200 ml. benzenc' then added; followed by about I50 m1;

of water; wa's-added-gradually by incr j mnts; until the solid 'mat'riaiwasuissoivea andff hydrolyzed: The aqueous layerwas separated jrom the supernatant" benzenesolution and-ex tracted with a small amount of fresh benzene.

The extract was added to the benzene solution and via's'- then 1 wasneu with' water "and aqueous sod chloride sdlu'tioii -t6remove free" acidity} aad' -d-isanea unuer rducedprssur'.-- Butyl hy 35 dracryl'ate was -c'ollected at" approximately 69 saturated-with an ly'ar n mofideana the" Wei/4.6 m

' h drnr stirrea fintothernixture while m in fie txi WilQ i-Q up per urei'wher'eupdfia white: olitl: hydroxyprop'i'onimino piopyl etlfef-hydrochlor H began to separate and thet6fiiperatur*of the reaction mixture roseto about-40 C. 0n stand- 01ing at room temperature" for'several days the tallinemass. Free 'hydrogen chloride was then" removed asdescribed in Example I, 300 ml; ben-= zene'*'were 'theu-added -and' theraction product?- hydrolyzed with approxinialtelydOdml. of'-'water',.-

' 3 which was added gradually until all the solid material was dissolved and hydrolyzed. The benzene layer was separated and treated with pow-- dered sodium bicarbonate to neutralize free acidity. The benzene solution was then distilled first at atmospheric pressure to remove benzene, water, and excess alcohol, and then under vacuum to recover propyl hydracrylate which was collected at about 61 C./1.7 mm.

Example IV Ethyl hydracrylate was obtained by the procedure of Example 111 using an equivalent amount of ethanol instead of n-propanol, the imino ether formed herein being beta-hydroxypropionimino ethyl ether hydrochloride.

Emample V Boiling pom O. at N d 10 mm. of Hg Ethylhydraerylata..- 76 1.4222 1.0589 n -Propyl hydracrylate 89 1. 4263 1.0243 n-Butylhydracrylata- 101 1.4292 1.0006 n-Octylhydracrylate... 150 1.4405 0.9488

Example VI A mixture of. 142 g. ethylene cyanohydrin, 375 g. beta-chloroallyl alcohol and 200 ml. diethyl ether was saturated with dry hydrogen chloride as described in Example I. No solid reaction 7 product was formed even on maintaining the reaction mixture at about to C. for one week. Excess hydrogen chloride wa then removed by the previously described procedure and the viscous reaction mixture was thoroughly stirred with 300 ml. of benzene. About 400 ml. of water were then added gradually, while coolin the mixture so as to keep the temperature below 50 C. A large amount of a white crystalline precipitate (beta-hydroxypropionimino betachloroallyl ether hydrochloride) was formed. Addition of water was continued until the precipitate was dissolved, the benzene layer was separated and washed successively with dilute aqueous solutions of sodium bicarbonate and sodium carbonate to neutralize free acidity. The benzene solution was then distilled first at atmospheric pressure to remove benzene, water and the unreacted chloroallyl alcohol and then under reduced pressure to recover the betachloroallyl hydracrylate which was collected at about 83 C./1 mm and had an index of refraction (N of 1.4680.

Example VII Allyl hydracrylate was obtained by an analogous'procedure of Example VI using an equivalent amount of allyl alcohol, the imino ether formed herein being beta-hydroxypropionimino allyl ether hydrochloride.

Although in the foregoing examples the process was conducted in the presence of diethyl ether as a diluent, and benzene was utilized as a solvent for the esters of hydracrylic acid, other organic solvents which are inert toward the reactants and reaction products may be utilized as solvents and diluents. Diethyl ether may be replaced, for example, by ethyl propyl ether, dipropyl ether, toluene, and ethylene dichloride, and other entrainers can be used in place of benzene.

Having thus described our invention, we claim:

1. A process comprising reacting an alcohol with ethylene cyanohydrin and hydrogen chloride under substantially anhydrous conditions, contacting the resulting product with water to produce an ester of hydracrylic acid corresponding to the alcohol used as the reactant, and re- 7 covering the formed ester of hydracrylic acid.

A process comprising reacting an alcohol of the formula ROH, wherein R represents a hydrocarbon radical free of substituents other than halogen, with ethylene cyanohydrin and hydrogen chloride under substantially anhydrous conditions to form the imino-ether hydrochloride corresponding to the formula wherein R. has the same significance as above, and hydrolyzing said imino-ether hydrochloride to the ester of hydracyclic acid having the formula wherein R has the same significance as above.

3. The process of producing an ester of hydracrylic acid comprising reacting an alcohol with ethylene cyanohydrin and anhydrous hydrogen chloride, under substantially anhydrous conditions, and in the presence of an inert organic solvent, and contacting the resulting product with water. 7

4. The process of producing an ester of hydracrylic acid comprising reacting an acrylic alcohol with ethylene cyanohydrin and anhydrous hydrogen chloride, under substantially anhydrous conditions, and in the presence of an inert organic solvent, and contacting the resulting product with water.

5. The process of claim 4 wherein the alcohol is a saturated alcohol.

6. The process of claim 4 wherein the alcohol is a monounsaturated olefinic alcohol.

'7. The process of claim 4 wherein the alcohol is a chloroallyl alcohol. a

8. The process of claim 4 wherein the alcohol is beta-chloroallyl alcohol.

9. The process of claim 4 wherein the alcohol is n-butyl alcohol.

10. The process of claim 4 wherein the alcohol is n-octyl alcohol.

11. Beta-chloroallyl hydracrylate.

12. An imino-ether hydrochloride corresponding to the general formula:

NH.HC1

HO-CHa-CHz-C 7 of the formula ROH, wherein R represents a hydrocarbon radical free of substituents other than halogen, with ethylene cyanohydrin and hydro 2,553,564 5 a 6 gen chloride under substantially anhydrous con- UNITED STATES PATENTS ditions to form the imino-ether hydrochloride 1 Number Name Date correspondmg to the formula 1,650,950 Matheson Nov. 29, 1927 NHHOI 2,122,716 Graves July 5, 1938 HO-OHz-CHrO 5 FOREIGN PATENTS OR Number Country Date wherein R has the same significance as above. 341,961 Great Britain Jan. 26, 1931 14. The process of claim 13 wherein R, is an unsaturated aliphatic radical. w

15. The process of claim 13 where R is the beta-chloroallyl radical.

16. The imino-ether hydrochloride of claim 12 wherein R, is the beta-chloroallyl radical. (1915)- y MARTIN L. FEIN H Karrer, Organic Chem1stry, 2nd ed., 1946, page CHARLES H. FISHER. 1.

REFERENCES CITED The following references are of record in the file of this patent: 20

' OTHER REFERENCES McElvain et al., J. Am. Chem. Soc., vol. 64, pp. 1825 1827 (Aug. 1942).

Drushel, Am. Jour. sci, vol. 40, pages 511-514 

1. A PROCESS COMPRISING REACTING AN ALCOHOL WITH ETHYLENE CYANOHYDRIN AND HYDROGEN CHLORIDE UNDER SUBSTANTIALLY ANHYDROUS CONDITIONS, CONTACTING THE RESULTING PRODUCT WITH WATER TO PRODUCE AN ESTER OF HYDRACRYLIC ACID CORRESPONDING TO THE ALCOHOL USED AS THE REACTANT, AND RECOVERING THE FORMED ESTER OF HYDRACRYLIC ACID. 